Sun Futing, Gao Zesen, Yang Yan, Chen Haijie
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Institute of Functional Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
ACS Appl Mater Interfaces. 2024 Oct 16;16(41):55666-55674. doi: 10.1021/acsami.4c09878. Epub 2024 Oct 3.
The halides have attracted much attention as novel solid electrolytes because of their easy synthesis, high electrochemical stability, and high ionic conductivities. However, the reported halides for solid electrolytes are still understudied compared with the oxides and sulfides. Here, we studied the Li-Fe-Cl phases that include LiFeCl and LiFeCl. Using the self-doping approach, a maximum ionic conductivity of 2.0 × 10 S cm at 50 °C was achieved for LiFeCl. It was improved by 3 orders of magnitude compared with that of LiFeCl (8.27 × 10 S cm at 50 °C). For the Li|LiFeCl|Li half-cell, it cycled for 2000 h at 50 °C under a current density of 0.01 mA cm, indicating an acceptable compatibility between LiFeCl and Li. Finally, an all-solid-state battery was successfully assembled with LiFeCl@LFP as the cathode, LiFeCl as the electrolyte, and a Li sheet as the anode. The initial specific charge capacity of the battery was 76.36 mAh g at 0.1C and 50 °C. The initial Coulombic efficiency was 73.06%. This study suggests LiFeCl as a new solid electrolyte, and the introduction of Li vacancies into the Li site is an efficient way to improve the electrochemical properties of halides.
卤化物因其易于合成、高电化学稳定性和高离子电导率而作为新型固体电解质备受关注。然而，与氧化物和硫化物相比，报道的用于固体电解质的卤化物仍研究不足。在此，我们研究了包括LiFeCl和LiFeCl的Li-Fe-Cl相。采用自掺杂方法，LiFeCl在50℃时实现了2.0×10 S cm的最大离子电导率。与LiFeCl（50℃时为8.27×10 S cm）相比提高了3个数量级。对于Li|LiFeCl|Li半电池，它在50℃、电流密度为0.01 mA cm下循环2000 h，表明LiFeCl与Li之间具有可接受的兼容性。最后，成功组装了以LiFeCl@LFP为正极、LiFeCl为电解质、锂片为负极的全固态电池。该电池在0.1C和50℃时的初始比充电容量为76.36 mAh g。初始库仑效率为73.06%。本研究表明LiFeCl是一种新型固体电解质，在锂位点引入锂空位是提高卤化物电化学性能的有效方法。
